Axial plunger pump



jY sUo KlTA mum. PLUNGER PUMP March 3; 1.9.70

2 Sheets-Sheet 1 Filed June 11, 1963 March 3,1970 YASUO KlTA 3,498,227

AXIAL PLUNGER PUMP Filed June 11, 1968 2 Sheets-Sheet 2 I I ///l' 72 770 I41 746 43/ (32 77b FIGS.

US. Cl. 1035 1 Claim ABSTRACT OF THE DISCLOSURE This invention provides improved axial plunger pumps in which containment of the thrust involved with the plunger piston operation can be achieved between a pair of disks fixed on the rotating shaft by supporting plunger pump mechanism between said disks so that no use of a thrust bearing is required for supporting the rotating shaft.

BACKGROUND OF THE INVENTION This invention relates to improved axial plunger pumps, more particularly to axial plunger pumps which can run at a high speed and high pressure.

Axial plunger pumps are known as particularly suited for a high speed and high pressure operation and attempts have been made to provide improved axial plunger pumps for various kinds of use. Generally speaking, however, conventional axial plunger pumps are very complicated in construction and expensive. The provision of a thrust bearing which has been considered heretofore as indisensable to axial plunger pumps makes a limitation of the running speed. The speed which can be obtained with conventional axial plunger pumps is relatively high but not so extremely high. In addition, the life of thrust bearings which are used is short.

The primary object of the invention is to provide new and improved axial plunger pumps which can dispense with any thrust bearing, whereby the above mentioned disadvantages which have been inevitable with conventional axial plunger pumps can be avoided.

Another object of the invention is to provide new and improved axial plunger pumps which are simple in constructions and can be economically manufactured.

A further object of the invention is to provide a new and improved means for cotnrolling the discharge of axial plunger pumps.

SUMMARY OF THE INVENTION The axial plunger pump of the type to which the invention is applied comprises a housing forming an enclosed chamber therein and having an inlet and an outlet. A driven shaft is rotatably supported by the housing to rotate within the enclosed chamber defined by the housing. A cylindrical barrel is mounted within the housing. This cylindrical barrel is provided with a central aperture having a diameter larger than the diameter of the driven shaft so that said driven shaft extends through the central aperture. The cylindrical barrel partitions liquid tightly in the discharge side of the chamber defined by the housing from the suction side of the chamber. The discharge side communicates with the outlet while the suction side communicates with the inlet. The cylindrical barrel is also provided with a plurality of cylindrical apertures extending in parallel to the axial direction of the shaft and satellitically arranged with respect to the central aperture.

According to the invention a pair of disks are fixed on the rotating shaft in such a spaced relationship that the distance between said pair of disks continuously varies A United States Patent "ice along the circular direction of arrangement of the above mentioned satellitic apertures. In an embodiment of the invention one disk extends in a plane normal to the axis of the rotating shaft while the other extends an inclined plane with respect to the axis of the shaft. The above mentioned relationship between the two disks can also be achieved by using two differently, for example, symmetrically inclined plates. In any case, the two disks are spaced from the opposite ends of the cylinder barrel, respectively.

According to the invention, an extensible plunger assembly is inserted in each of the satellitically arranged apertures of the cylinder barrel. The extensible plunger assembly comprises a pair of axially slidable plug members inserted in the cylindrical aperture to close the opposite end openings thereof in such a spaced relation as to form an extensible pump chamber therebetween and a spring inserted therebetween for urging them to be alienated from each other. The outer ends of the slidable plug members engaging sealingly and slidably with the two disks at their opposed surfaces, respectively.

Means are provided for communicating the pump chamber in each of the satellitically arranged apertures selectively with the suction and discharge side of the chamber defined by the housing so that the liquid to be pumped, for example, oil is introduced from the suction side to the pump chamber and then discharged from the pump chamber to discharge side during the extension and retraction operation of the plunger assembly, respectively.

In a preferred embodiment of the invention, each of the pump chambers is communicated with the discharge side of the chamber defined by the housing through a check valve and means are provided for communicating the pump chamber with the suction side of a chamber defined by the housing through an opening formed in at least one of the two disks and a passageway formed in the slidable plug member engaging the disk having said opening. The passageway of the slidable plug member is capable of communicating with said opening of said disk during the extension stroke of the plunger assembly.

In the above mentioned manner, containment of the thrust produced with the plunger piston operation can be achieved between a pair of disks fixed on the rotating shaft so that no use of a thrust bearing is required'for supporting the rotating shaft. No use for any thrust bearings enables the axial plunger pump to run at a much higher speed than possible with use of a thrust bearing.

The cylinder lbarrel having a plurality of pump chambers may be so mounted within the housing as to be movable in the direction of the axis of the rotating shaft. In such an embodiment if a port is provided for communicating the pump chamber with the suction side of the chamber defined by the housing when the plunger assembly is in an extended position, it becomes possible to control the discharge by changing the relative position of the plunger assembly with respect to the cylinder barrel since the effective stroke of each of the plunger assemblies is changed accordingly. 1

Other features and advantages of the invention will become apparent from the detailed description of the preferred embodiments of the invention with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a longitudinally sectional view, taken along the line 11 of FIGURE 2, of an axial plunger pump showing an embodiment of the invention;

FIGURE 2 is a vertical sectional view at the line 22 of the FIGURE 1;

FIGURE 3 is a vertical sectional view at the line 33 of FIGURE 1;

. 40. The endv surface. 48 of the .slidable member 41 which FIGURE 4 is a longitudinal sectional view of an axial.

plunger pump similar to FIGURE 1 showing another embodiment of the invention; and

FIGURE 5 is a longitudinal sectional view" of an axial plunger pump similar to FIGURE 1 showing a further embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, especially to FIGURES l to 3, there is illustrated an axial plunger pump including a housing or casing generally indicated as 11. The housing 11 comprises a pair of members 11a and 1112 which cooperate to form an enclosed chamber 12 having an inlet 13 and an outlet 14. The reference numeral 15 indicates a screw connecting the cooperating members 11a and 11b to each other and the reference numeral 16 indicates packing seal means at contact surfaces of the cooperating members 11a and 11b. The member 11a has an end opening 17 for receiving a bearing 18 which in turn supports rotata bly a driven shaft 19. The reference numeral 20 indicates an end cover plate having oil seal means 21 for sealingly closing the opening 17 of the member 11a.

The driven shaft 19 which extends into the chamber 12 is connected to a drive mechanism (not shown) at the outside of the housing 11. A pair of disks 22 and 23 are fixed on said driven shaft 19 within the enclosed chamber 12. The disk 22 is mounted on the shaft in a normal relation to the axial direction thereof while the disk 23 is an inclined plate so that the distance between the two disks 22 and 23 continuously varies along a circular direction. The disk 22 is secured by a screw 24 to the shaft 19 and the inclined disk 23 is secured by means of a key 25 and a nut 26 to the inner end of the shaft 19.

Within the housing 11 there is mounted a cylinder barrel 27 which is provided with a central aperture 28 having a diameter larger than the outer diameter of the shaft 19 so that the shaft 19 extends through the aperture 28. The cylindrical barrel is secured by screws (only one of which is indicated as 29) to the member 11a in a sealing engagement with use of O-rings 30 so that the outlet 14 is liquid-sealed tightly by the cylinder barrel pertitioned from the chamber 12. The cylinder barrel 27 is provided at its outer periphery with an annular recess 31 which communicates with the outlet 14. The cylinder barrel 27 is also provided with a plurality of elongated cylindrical apertures 32 arranged in a circle around the shaft 19, in other words, satellitically with respect to the central apertures 28, and extending in directions parallel to the shaft 19.

In each of the cylindrical apertures 32 there is inserted an extensible plunger assembly generally indicated as 40. The extensible plunger assembly comprises a pair of slidable plug members 41 and 42 inserted in the cylindrical apertures 32 to close the opposite end openings thereof, respectively, so as to form a pump chamber 44 therebetween in cooperation with the cylindrical apertures 32. A coil spring 43 is inserted between the inner ends of the slidable plug members 41 and 42 so as to urge the slidable members 41 and 42 outwardly, respectively. The outer ends of the slidable members 41 and 42 abut sealingly and slidably on the opposed surfaces 22a and 23a of the disks 22 and 23, respectively. The outer end of the member 41 is in direct contact with the surface 22a while the outer end of the member 32 engages through a swivel block 45 with the surface 23a.

The slidable member 41 is formed with a through oil passageway 46 for introducing oil into the pump chamber 44 through a window opening 47 formed in the perpendicular disk 22. The window opening 47 is of an elon gated arc form as shown in FIGURE 2 so that the passageway 46 may communicate with the chamber 12 only for a certain rotating angle of the disk 22 which corresponds to the extension stroke of the plunger assembly is in contact with the inner surface 22a of the disk 22 is provided with a central cavity 49 and an annular recess 50 so that the oil pressure which will be produced in the pump chamber 44 is supplied between the contact surfaces 48 and 22a so as to provide a static pressure bearing system. In order to provide static pressure bearng system between the swivel block 45 and the surface 23a of the disk 23 as well, the slidable member 42 is provided with an oil passageway 51 extending in its axial direction and communicating with a central port 52 which is formed in the swivel block, 45. The swivel block 45 is provided with a central cavity 53 and an annular recess 54 at its end surface 55 which is always in contact with the surface 23a of the inclined disk 23. The port 52 communicates the central cavity 53 with the oil passageway 51.

The pump chamber 44 of each of the cylindrical apertures 32 is communicated to the annular recess 31 through a check valve means 56 which allows the pressure oil to lbe discharged to the annular recess 31 and then to the outlet 14.

The driven shaft 19 is provided with an axial oil passageways 60 and a pluarlity of radial oil passageway 61. The axial passageway 60 is opened at its one end to the chamber near the inlet 11 and communicated at its inner end with the radial passageways 61 which are in turn opened at the position near the opposite surface of the perpendicular disk 22 to the surface 22a. The shaft 19 is also rotatably carried by a needle bearing 70 which is in turn supported by the cylinder barrel 27 at its central aperture 28.

The operation of the apparatus illustrated in FIGURES 1 to 3 is as follows:

When the shift 19 is driven to rotate, the two disks 22 and 23 are rotated with the outer ends of the slidable members 41 and the swivel blocks 45 engaging with the slidable members 42 sliding on the opposed surfaces 22a and 23a of the disks 22 and 23, respectively, under pressure and sealing condition. The distance between the two disks 22 and 23 at the position of each of the plunger assemblies 40 varies continuously. While the slidable member 41 abuts against the disk 22 perpendicular to the axis of the shaft, there is no substantial movement of the member '41, the other slidable member 42 abutting against the inclined disk is enforced to a reciprocating movement along the cylindrical aperture 32 whereby the volume of the pump chamber 44 is varied. In the extension stroke of the plunger assembly 40, oil flowing into the chamber 12 from the inlet 13 and passing through the passageways 60 and 61 is introduced to the pump chamber 44 through the window opening 47 of the disk 22 and the passageway 46 of the member 32, while the check valve 56 is in a closed position. This is the suction stroke. During the retraction stroke of the plunger means 40, pressure oil is discharged through the check valve 56 to the annular recess 31 which is communicated with the outlet 14, while the slidable member 41 travels the blind portion of the disk 22 so that the passageway 46 is kept in a closed condition.

According to the invention the thrust due to the pumping operation of plunger assemblies 40 is fully supported by the two disks 22 and 23-. The shaft 19' can, therefore, be supported by radial bearings 18 and 70 alone and dispense with any thrust bearing.

Another embodiment of the invention is illustrated in 'FIGURE 4, in which the same reference numerals as used in FIGURE 1 indicate the corresponding parts, respectively. In the modification shown in FIGURE 4, a pair of inclined disks 122 and 123 are fixed on the driven shaft 19. These two disks 122 and 123 extend symmetrically inclined planes, respectively, with respect to the axisof the shaft 19 so that both the two slidable members 141 and 142 which correspond to the members 41 and 44 illustrated in FIGURE 1 are enforced to simultaneous axially reciprocating movements which cooperate to produce the expansion and contraction operation of the pump chamber 44 formed between them. The engagement of the member 141 to the inclined disk 122 is carried out in the same manner as the engagement of the member 142 to the inclined disk 123. The latter is thus similar to the engagement of the member 42 to the inclined disk 23 illustrated in FIGURE 1. The reference numeral 145 indicates the swivel block similar to the swivel block 45 of FIGURE 1. Introduction of oil from the chamber 12 into the pump chamber 44 is carried out through both the passageways 146 and 151 which can communicate through central ports 152 with window openings 147 and 148 formed in the inclined disks 122 and 1.23, respectively. Each of the window openings 147 and 148 is formed in a similar manner to the window opening 47 of the disk 47 shown in FIGURE 1. The structure and the operation of the other parts of the embodiment of FIGURE 4 are substantially identical with those of corresponding parts illustrated in FIGURES 1 to 3.

A further modified embodiment of the invention is illustrated in FIGURE 5, in which the same reference numerals as used in FIGURE 1 indicate the corresponding parts, respectively. In the embodiment shown in FIGURE 5, the cylinder barrel 227 is engaged within the housing 11 so as to be slidable in an axial direction with the sealing angagement between the outer periphery of the barrel 227 and the inner wall of the housing 11 being maintained. The reference numeral 201 indicates a screw for driving the cylinder barrel 227. The screw 201 is operable by a handle 202 outside of the housing. In connection of the slide movement of the cylinder barrel, importance exists in the provision of a port for communicating each of the pump chambers 44 with the suction side of the chamber 12 when each of the plunger members 42 is in a retracted position with the plunger assembly 40 being in an extended state. It will be apparent that so far as the pump chamber is communicated through a port 203 with the suction side, no pumping operation can be effected. The effective discharging operation starts after the inner end of the plunger member 42 goes leftwardly over the port 203. Accordingly, the effective stroke of the plunger member 42 can be changed by moving the barrel 227 in an axial direction to change the relative position of the port 203 to the plunger member 42, whereby the discharge can be controlled at will. The structure and the operation of the other parts illustrated in FIGURE 5 are substantially identical with those of the corresponding parts illustrated in FIGURE 1.

What I claim is:

1. An axial plunger pump comprising:

a housing forming an enclosed chamber having an inlet and an outlet, said inlet being at one end of the housing and said outlet being intermediatelly disposed on the housing;

a driven shaft rotatably mounted axially within the enclosed chamber;

a bearing arranged in the housing at the end remote from the chamber inlet which bearing mounts the driven shaft for rotational movement;

a cylindrical barrel having an external centrally disposed annular recess, a central through aperture, a plurality of through apertures satellitically arrangedwith respect to the central aperture and a port extending from each of the satellitically arranged through apertures to the annular recess, said cylindrical barrel being mounted within the housing in liquid sealing relationship and located to provide alignment of the annular recess with the chamber outlet;

a first disk fixedly mounted on the driven shaft adjacent the cylindrical barrel and in proximity to the bearing mount, said first disk being disposed perpendicularly to the driven shaft;

a second disk fixedly mounted on the driven shaft adjacent the end of the cylindrical barrel remote from the first disk, the second disk being inclined with respect to the axis of the shaft;

a plurality of extensible plunger assemblies located in the satellitically arranged aperture in the cylindrical barrel, each of said plunger assemblies comprising a first and a second slidably arranged section having axial through bores and a spring located between the sections to bias the sections away from each other and into engagement with the first and second disks respectively;

a check valve in each of the ports between the satellitically arranged apertures in the cylindrical barrel and the annular recess;

means for effecting communication between the chamber inlet and the axial bores in each of the plunger assemblies, comprising an axial through bore in the driven shaft, radially extending bores in the driven shaft extending perpendicularly from the axial passageway in the driven shaft at a location adjacent to the first disk on the side thereof remote from the plunger assemblies, and a window opening in the first disk aligned with the bores in the plungers and extending for a length of at least two plunger openings; and

a needle bearing arranged in the central aperture of the cylindrical barrel of the end nearest the inlet to support the driven shaft.

References Cited UNITED STATES PATENTS 2,286,301 6/1942 Parsons 103173 2,709,339 5/1955 Edelman et al. 103173 2,821,932. 2/1958 Lucien 103-173 2,842,068 7/1958 Sundin 103-173 2,990,781 7/1961 Tuck et a1 103173 3,085,514 4/1963 Budzich 103-173 3,125,034 3/1964 Lucien et al. 103-174 3,265,008 8/1966 Ward 103-162 FOREIGN PATENTS 1,188,441 3/1959 France.

WILLIAM L. FREEH, Primary Examiner U.S. Cl. X.R. 103l73 

